Device display or portion thereof with a messaging graphical user interface



The FIGURE is a front view of a device display or portion thereof with a messaging graphical user interface showing the present design.

The broken lines showing the mobile device is provided for the purposes of illustrating environmental structure and forms no part of the claimed design. Furthermore, the broken lines showing the display screen and elements of the graphical user interface represent the portions of the article that form no part of the claimed invention. 

CLAIM The ornamental design for a device display or portion thereof with a messaging graphical user interface, as shown and described. 